There are many different types of sensors in which an accurate determination of the rotational position of the sensor or an accurate orientation of the sensor is necessary. Examples of such are high-resolution camera sensors of near-earth satellites or of surveillance aircraft or unmanned aerial vehicles (UAV).
The rotational position of sensors may take place locally, for example, by means of a mechanical, electrical, or optical device, for example a gyroscope, a MEMS, a fiber optic gyroscope, or magnetohydrodynamic sensors. In addition, the rotational position determination of the sensor may also be determined by means of so-called star trackers, which use fixed stars as a reference source.